Repositorio Digital Universidad Simón Bolívar
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Segmentación de glioma de alto grado en imágenes de resonancia magnética
No full textThrough this work we propose a computational technique
for the segmentation of magnetic resonance images
(MRI) of a brain tumor, identified as high grade glioma
(HGG), specifically grade III anaplastic astrocytoma. This
technique consists of 3 stages developed in the threedimensional
domain. They are: pre-processing, segmentation
and post-processing. The pre-processing stage uses
a thresholding technique, morphological erosion filter
(MEF), in gray scale, followed by a median filter and a
gradient magnitude algorithm. On the other hand, in order
to obtain a HGG preliminary segmentation, during the
segmentation stage a clustering algorithm called region
growing (RG) is implemented and it is applied to the preprocessed
images. The RG requires, for its initialization, a
seed voxel whose coordinates are obtained, automatically,
through the training and validation of an intelligent operator
based on support vector machines (SVM). Due to
the high sensitivity of the RG to the location of the seed,
the SVM is implemented as a highly selective binary classifier.
During the post-processing stage, a morphological
dilation filter is applied to preliminary segmentation generated
by RG. The percent relative error (PrE) is considered
by comparing the segmentations of the HGG, generated
manually by a neuro-oncologist, with the dilated segmentations
of the HGG, obtained automatically. The combination
of parameters linked to the lowest PrE, allows establishing
the optimal parameters of each computational
algorithms that make up the proposed computational
technique. The obtained results allow reporting a PrE of
11.10%, which indicates a good correlation between the
manual segmentations and those produced by the computational
technique developed.A través de este trabajo se propone una técnica computacional
para la segmentación de un tumor cerebral,
identificado como un glioma de alto grado (HGG) de tipo
astrocitoma anaplásico de grado III, que está presente en
las imágenes de resonancia magnética (MRI). Esta técnica
consta de 3 etapas desarrolladas en el dominio tridimensional.
Ellas son: preprocesamiento, segmentación y
postprocesamiento. La etapa de preprocesamiento utiliza
una técnica de umbralización, un filtro de erosión morfológica
(MEF), en escala de grises, seguido de un filtro de
mediana y de un algoritmo de magnitud de gradiente. Por
otro lado, con el propósito de generar una segmentación
preliminar del HGG, durante la etapa de segmentación se
implementa un algoritmo de agrupamiento, llamado crecimiento
de regiones (RG), que se aplica a las imágenes
preprocesadas. El RG requiere para su inicialización la ubicación
de un vóxel semilla cuyas coordenadas se obtienen,
automáticamente, a través del entrenamiento y la validación
de un operador inteligente basado en máquinas de
vectores de soporte (SVM). Debido a la alta sensibilidad
del RG a la ubicación de la semilla, la SVM se implementa
como un clasificador binario altamente selectivo. Durante
la etapa de post-procesamiento, se aplica un filtro de dilatación
morfológica a la segmentación preliminar, generada
por RG. El error relativo porcentual (PrE) se considera
para comparar las segmentaciones de la HGG generadas
de forma manual por un neurooncólogo, con las segmentaciones
dilatadas de la HGG, obtenidas automáticamente.
La combinación de parámetros vinculados al PrE más bajo
permite establecer los parámetros óptimos de cada uno de
los algoritmos computacionales que componen la técnica
computacional propuesta. Los resultados obtenidos permiten
reportar un PrE de 11.10%, lo cual indica una buena
correlación entre las segmentaciones manuales y las producidas
por la técnica computacional desarrollada
Executive functioning in primary school children in public and private school of Cúcuta-Colombia: Contributions to neuropsychological therapy
No full textEl estudio analizó la relación entre el funcionamiento ejecutivo y las características
sociodemográficas de niños en inicio de edad escolar en Cúcuta, mediante la descripción de
las características de sueño, hábitos de estudio, acompañamiento extraescolar, nivel
socioeconómico y otras condiciones sociodemográficas de los padres en relación con el nivel
de desempeño en funciones ejecutivas. El estudio se desarrolló mediante un método de tipo
cuantitativo, con un diseño no experimental, transversal, de alcance correlacional con una
muestra conformada por 60 niños y niñas de un colegio público y uno privado ubicados en la
ciudad de Cúcuta, con edades entre los 5 y 7 años. Se encontró que el nivel funcionamiento
ejecutivo se ubica dentro del promedio en ambos contextos escolares, sin embargo hay
características particulares del escenario privado como el mayor acompañamiento extraescolar,
motivación a que los niños duerman sin compañía de sus padres y la convivencia con ambos
padres, factores que han mostrado beneficios en el desarrollo psicológico infantil. Por el
contrario, en el contexto escolar público, se evidenció un mayor tiempo en horas de sueño, lo
cual se ha relacionado con mejor desempeño cognitivo en general. Se concluye, que las
variables que muestran mayor relación con la función ejecutiva son el nivel socioeconómico, la
edad de los padres y su nivel de formación. El número de horas de sueño, también mostró
relación positiva específicamente con la capacidad de control inhibitorio y la memoria de
trabajo. Se discuten los resultados a la luz de estudios previos, cuyos aportes pueden ser
utilizados en beneficio de la terapéutica psicológica y la prevención.The study analyzed the relationship between executive functioning and the sociodemographic
characteristics of children at the beginning of school age in Cúcuta, by describing sleep
characteristics, study habits, extracurricular accompaniment, socioeconomic status and other
sociodemographic conditions of parents in relation to with the level of performance in executive
functions. The study was developed using a quantitative method, with a non-experimental,
cross-sectional design, correlational in scope with a sample consisting of 60 children from a
public and a private school located in the city of Cúcuta, ages 5 and under. and 7 years. It was
found that the level of executive functioning is within the average in both school contexts,
however there are particular characteristics of the private scenario such as the greater
extracurricular accompaniment, motivation for children to sleep without their parents' company
and coexistence with both parents. that have shown benefits in children's psychological
development. On the contrary, in the public school context, there was a greater time in sleep
hours, which has been related to better cognitive performance in general. It is concluded that
the variables that show greater relation with the executive function are the socioeconomic level,
the age of the parents and their level of education. The number of hours of sleep, also showed
positive relationship specifically with the capacity of inhibitory control and working memory. The
results are discussed in light of previous studies, whose contributions can be used for the
benefit of psychological therapy and prevention
Estimación del tamaño de hematomas epidurales en imágenes de tomografía computarizada: estudio comparativo entre métodos lineales y volumétricos
No full textThis work evaluates the performance of some
methods employed for assessing the volume of
seven subdural hematomas (EDH), present in
multi-layer computed tomography images. Firstly, a reference
volume is considered to be that obtained by a neurosurgeon
using the manual planimetric method (MPM).
Secondly, the volume of the 7 EDHs is obtained considering
both the original version of the ABC/2 method and two of
its variants, identified in this paper as ABC/3 method and
2ABC/3 method. The ABC methods allow for calculation
of the volume of the hematoma under the assumption
that the EDH has an ellipsoidal shape. In third place, an
intelligent automatic technique (SAT) is implemented that
generates the three-dimensional segmentation of each
EDH and from it the volume of the hematoma is calculated.
The SAT consists of the pre-processing, segmentation
and post-processing stages. In order to make judgments
about the performance of the SAT, the Dice coefficient
(Dc) is used to compare the dilated segmentations of the
EDH with the EDH segmentations generated manually. Finally,
the percentage relative error is calculated as a metric
to evaluate the methodologies considered. The results
show that the SAT method exhibits the best performance
generating an average percentage error of less than 2%
Flow regulation at constant head in feedwater pumps in a sugar industry
No full textIn this paper the feasibility of energy saving by implementing flow regulation at constant load in feedwater pumps in a sugar industry is studied. As regulation strategy, the use of a variable speed drive in the hydraulic system is proposed. For the project evaluation, the Net Present Value and Payback Period techniques are used. Among the variables considered are the price of energy, the equipment useful life, financial data and those related to environmental impact. As a result, it was found that if only a commercial approach is considered, the energy saving strategy is profitable but not attractive, because investment is recovered in a period close to the useful life of technology. However, if a government focus that encourages the implementation of these energies saving strategies is considered, the investment of the project recovers in a short time
Neurofeedback effects on cognitive performance in children with attention deficit
No full textThe objective of this research was to analyze the effects of
an intervention program through neurofeedback, on the cognitive
performance in children with inattention indicators. A
quasi-experimental pretest-posttest study was used under a
positivist epistemology, with a comparative analysis for each
evaluated cognitive process. A sample of 29 cases was intentionally
selected from a group of children and young adolescents
with low performance indicators from a Therapeutic
Center from Cucuta-Colombia. The neurofeedback program
was developed in 20 sessions with the purpose of increase
low-beta waves (12-16 Hz) and inhibition theta waves (4-7
Hz). A comparative statistically analysis with five months of
difference was carried out using Wilcoxon test, finding significant
differences between the pretest and the posttest in
neuropsychological tests of auditory-visual attention, encoding
memory and planning. The results are discussed with empirical
backgrounds that have shown positive effects in this
type of interventions
Neuropsychological Performance in Patients with Asymptomatic HIV-1 Infection
No full textHuman immunodeficiency virus (HIV-1) infection and acquired immunodeficiency syndrome (AIDS) lead to neurocognitive disorders; however, there is still much knowledge to be gained regarding HIV-associated neurocognitive disorders. The purpose of this study was to assess the cognitive performance, instrumental activities of daily living, depression, and anxiety in patients with asymptomatic HIV-1 infections compared with seronegative participants without neurocognitive impairment. We studied a sample consisted of 60 patients with asymptomatic HIV-1 infections and 60 seronegative participants without neurocognitive impairment from the city of Barranquilla, Colombia, with a mean age of 36.07 years. A protocol of neuropsychological and psychopathological tests was applied to the participants. The group of patients with asymptomatic HIV infections significantly underperformed on tasks that assessed global cognitive screening, attention span, learning, phonemic verbal fluency, auditory-verbal comprehension, information processing speed, cognitive flexibility, and motor skills compared to the group of seronegative participants. No significant differences were found in memory, visual confrontation naming, vocabulary, inhibition, and instrumental activities of daily living. Additionally, the patients with asymptomatic HIV-1 infection had a higher anxiety index than the seronegative participants, but no significant difference was found in depression. A correlation was found between depression and anxiety. In conclusion, the patients with asymptomatic HIV-1 infection had lower cognitive performances than the seronegative participants in the cognitive functions mentioned above and more anxiety but still performed the instrumental activities of daily living
Elements of financial valuation in small and medium Colombian companies
No full textEl presente Artículo, tuvo como objetivo determinar los elementos de valoración financiera en pequeñas y medianas empresas Colombianas. Se sustentó en Porter (1985), Porter, y Kramer (2011) y ACCID (2009), entre otros. La investigación es de tipo descriptiva, no experimental, de campo. Se aplicó una entrevista estructurada. Sus resultados fueron que la mayoría de empresas valoradas por cualquiera de los métodos arroja valores sorprendentes, las metodologías incorporan al procedimiento el potencial de la empresa generando utilidades en el futuro a través del flujo de caja a perpetuidad, como también el valor de mercado de sus activos.The purpose of this article was to determine the elements of financial valuation in small and medium-sized Colombian companies. It was based on Porter (1985), Porter, y Kramer (2011) y ACCID (2009), among others. The research is descriptive, not experimental, field. A structured interview was applied. Its results were that most companies valued by any of the methods yields surprising values, methodologies incorporate the potential of the company in the future by generating future profits through cash flow in perpetuity, as well as the market value of its assets
Anxiety and Depression in Patients Hospitalized With Chronic Kidney Disease in Barranquilla Clinics, Colombia
No full textThe purpose of this study is to determine the levels of anxiety and depression in patients aged between 18 and 70
years, hospitalized with chronic kidney disease in a clinic entity of the city of Barranquilla.
The type of research is descriptive, presenting the information through the indicators and statistical tables, the
Hospital Scale of Anxiety and Depression of, Zigmond & Smith (1983), which evaluates the detection of
depressive and anxious disorders in the non-psychiatric hospital context. The application of the Scale was
performed in the hospital entity of the city of Barranquilla to 50 patients with Chronic Kidney Disease. The results
they are beneficial in the short term, because they create new research proposals applied to another population
group diagnosed with chronic diseases, especially for the evaluation and intervention in the area of health
psychology. In the long term, new theories, methods of intervention and evaluation applied to the population of
patients with chronic kidney disease will be studied. In the same way, the results show marked trends related to
depression, an aspect that is consistent with the deterioration that affects the individual in the course of the disease
and also show a positive correlation of the study variables, depression and anxiety disorders in patients with CKD
can be due to a symptomatology or consequence of psychological burnout
Cognitive and neuropsychological factors in the decision to use drugs. Elements to take into account in psychological therapy
No full textIntroducción: La drogadicción es una pandemia que afecta a 324 millones de consumidores y que en Colombia un 63% de estudiantes informan haber consumido algún tipo de droga, los gobiernos en su afán de intervenir la problemática han buscado reducir la oferta con resultados negativos y de comprender la demanda con tesis neuropsicológicas que explican el mantenimiento de la conducta además de buscar comprender que lleva a los sujetos a elegir y realizar la primera conducta de consumo. Ante esta última premisa el estudio busca identificar y describir las relaciones existentes entre factores cognitivos como la intencionalidad y las funciones ejecutivas de inhibición, planeación y toma de decisiones en los procesos de elección y realización de esta conducta en los adolescentes.
Metodología: En una muestra de 80 estudiantes se realizó un estudio cuantitativo de tipo descriptivo y correlacional al cual se le aplico el Emiud para evaluar la intención de consumo, laberintos y torres para planeación, laberintos y stroop para inhibición y juego de carta de Iowa para toma de decisiones.
Resultados: El 51% de estudiantes informa no tener seguridad de no consumir una droga y un 14% informar tener la intención de consumir, además cuando la intención es positiva se acompaña de actitudes, norma subjetiva y control conductual también positivas, las cuales se correlacionan de forma negativa con la planeación, inhibición y toma de decisiones.
Discusión: Los estudiantes con intención de consumir una droga presentan una inhibición con tendencia impulsiva y automática, planeación de corto plazo y una toma de decisiones con riesgo.Introduction: Drug addiction is a pandemic that affects 324 million consumers and that in Colombia 63% of students report having used some type of drug, governments in their eagerness to intervene the problem have sought to reduce supply with negative results and Understanding the demand with neuropsychological theses that explain the maintenance of behavior as well as seeking to understand what leads subjects to choose and perform the first consumption behavior. Given this last premise, the study seeks to identify and describe the existing relationships between cognitive factors such as intentionality and executive functions of inhibition, planning and decision making in the processes of choosing and performing this behavior in adolescents.
Methodology: In a sample of 80 students a descriptive and correlational quantitative study was carried out to which the Emiud was applied to evaluate the intention of consumption, labyrinths and towers for planning, mazes and stroop for inhibition and Iowa letter game for decision making.
Results: 51% of students report not being sure not to consume a drug and 14% report having the intention to consume, in addition when the intention is positive it is accompanied by positive attitudes, subjective norms and behavioral control, which are correlated in a negative way with planning, inhibition and decision making.
Discussion: Students with the intention of consuming a drug have an inhibition with impulsive and automatic tendency, short term planning and risky decision making
Training for entrepreneurship in e-government in Pacific Alliance Countries
No full textEl objetivo es conocer sobre la formación para el
emprendimiento en los países de la Alianza del
Pacífico, a través de los sitios Web en el gobierno
electrónico. Se empleó la metodología cualitativa,
paradigma interpretativo y técnica de observación. En
los cuatro países de la Alianza se evidenció una
administración electrónica inclusiva e imparcial
(eInclusión). Chile con la formación con enfoque de
género, Colombia en la triada Estado-academiaempresa,
México con metodología lúdico-pedagógica y
Perú con los Massive Open Online Course.The objective is to learn about entrepreneurship
training in the countries of the Pacific Alliance,
through Web sites in e-government. The qualitative
methodology, interpretative paradigm and observation
technique were used. An inclusive and impartial
electronic administration (eInclusion) was evident in
the four countries of the Alliance. Chile with training
with a gender focus, Colombia in the state-academycompany
triad, Mexico with play-pedagogical
methodology and Peru with the Massive Open Online
Course